Immunofluorescent distribution of postribosomal particles during oogenesis and early development of an insect (Dysdercus intermedius, Heteroptera, Pyrrhoc.).

During previtellogenesis, the oocytes of the telotrophic meroistic ovary ofDysdercus are provided with ribosomes and ribonucleoprotein (RNP) particles by the nurse cells. At the end of vitellogenesis, the oocyte itself becomes active as shown by autoradiography. The proteins synthesized by the oocyte are stored in cytoplasmic postribosomal particles which are preformed by the tropharium. The proteins of these particles were separated by SDS polyacrylamide gels and their endogenous oocyte proteins revealed by fluorography. The synthesis, transport, and storage of the postribosomal particles are demonstrated by indirect immunofluorescence. The young oocytes of previtellogenic follicles show a diffuse distribution of these particles. In late vitellogenesis, fluorescence becomes more and more concentrated in spots throughout a distinct region in the middle part of the oocyte. Thus, in freshly laid eggs, the periplasm is free of fluorescence. During migration of the cleavage nuclei the postribosomal particles were shifted into the cortex. Fluorescence is then most intense in the periplasmic region. During blastoderm formation, however, fluorescence decreases.